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New technologies in polymer synthesis and pipe extrusion equipment have led to the commercialization of high-performance, large-diameter, thick-wall high density polyethylene (HDPE) pipes. They have been used in the field of seawater transport and cooling to replace metal pipes, due to their advantages of high corrosion resistance and extensibility. Connection of HDPE pipe is important as it determines the safety of the entire piping system. Butt fusion welding is commonly used for HDPE pipe connection but may cause the formation of weak points in the welded joints, interfering the reliability of the pipeline system in the application of nuclear power plants. At present, there is a lack of research on evaluating the performance of welded joint for large-diameter thick-wall HDPE pipes made by butt fusion-welding. The purpose of this study is to investigate the influence of three different butt fusion-welding processes, i.e., single low pressure (SLP), single high pressure (SHP) and dual low pressure (DLP), by evaluating the performance of their welded joints, including characterizing tensile strength, extensibility, crystallinity and hardness. In specific, a thick-wall HDPE pipe with OD of 812.8 mm and wall thickness of 74 mm which is certified for nuclear safety class was used for study. Representative specimen from the outer, middle and inner part across the wall of the main pipe body and welded joints were taken for testing. Different test methods and specimens were designed to assess the feasibility of evaluating the welding performance from different welding process. The results showed that the mechanical properties of different locations of the welded joints were different, and the tensile strength and fracture energy of the middle part of the joint were lower than that of the inner and outer parts, which could be caused by the difference in the crystallinity and thickness of the melting zone influenced by welding processes, as can be seen from the analysis of DSC test and morphology observation. Hardness testing was conducted on the section of the welded joints, and it revealed that the micromechanical properties of the welded joints in the region of the heat-affected zone were enhanced significantly, which may be due to the annealing effect caused by welding process. In summary, The DLP process resulted in the best extensibility of the welded joints among three processes, suggesting that the joining pressure from welding process plays an important role in affecting the extensibility of the welded joints.

Abstract The early diagnosis of Parkinson's disease (PD) provides opportunities for early intervention to slow the progression of neurological degeneration in patients, particularly as the aging population increases in our society. Among a series of pathological features of PD, mitochondria abnormalities have been identified as central event that occurs at the early stage of PD. However, the method for detecting mitochondrial abnormalities‐associated early PD has not been fully developed. We herein report a specifically mitochondrial targeting probe (named TPA‐BT‐SCP) that is able to characterize mitochondria abnormalities for early diagnosis of PD and monitor PD neurodegenerative progress. The probe is an aggregation‐induced emission (AIE) probe with a strong positive charge, a 3D distorted molecular structure, and a separated HOMO‐LUMO distribution, designed with unique molecular design guidelines. Our research demonstrated that TPA‐BT‐SCP could emit stable and strong fluorescence, and rapidly accumulate in mitochondria due to the negative charge. After intranasal administration of 1‐methy‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐induced PD mice, TPA‐BT‐SCP successfully bypassed the blood−brain barrier to light up the brain, allowing the grading of PD severity based on its high sensitivity. Taken together, this work develops a novel AIE probe that exhibits dramatically high sensitivity to mitochondrial changes and enables noninvasive diagnosis of early PD in the brain.

Blaps rynchopetera Fairmaire has long been used as a folk medicine by the Yi and Bai ethnic groups in China to treat fever, cough, gastritis, boils, and tumors. In the present study, the cytotoxicity of the defensive secretion (TDS) of B. rynchopetera against AGS Caco-2, HepG2 U251 and Bel-7402 was tested, and the results revealed that TDS had potent cytotoxicity against testing cells with IC50 values of 45.8, 17.4, 53.6, 98.4 and 23.4 μg/mL, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis was employed to clarify the cytotoxic constituents in TDS of B. rynchopetera and five volatile compounds, including 2-ethyl-2,5-cyclohexadiene-1,4-dione (3, 31.00%), 1-tridecene (5, 28.02%), 2-methyl-2,5-cyclohexadiene-1,4-dione (2, 22.86%), hydroquinone (4, 1.33%), and p-benzoquinone (1, 1.01%), were identified. Chemical constituent investigation on TDS further supported the presence of 5 above compounds. A cytotoxic assay indicated that compounds 1, 2, 3 and 4 exhibited significant cytotoxicity against the testing cell lines, implying that benzoquinones and hydroquinone played important roles in the cytotoxicity of TDS of B. rynchopetera. TDS is a cytotoxic natural material and further studies investigating mechanisms and inhibitory activities on other cell lines is warranted.